#ifndef _MEMDC_H_
#define _MEMDC_H_

//////////////////////////////////////////////////
// CMemDC - memory DC
//
// Author: Keith Rule
// Email:  keithr@europa.com
// Copyright 1996-1997, Keith Rule
//
// You may freely use or modify this code provided this
// Copyright is included in all derived versions.
//
// This class implements a memory Device Context

class CMemDC : public CDC 
{
protected:
	CBitmap  m_bitmap;       // Offscreen bitmap
	CBitmap* m_oldBitmap;    // bitmap originally found in CMemDC
	CDC*     m_pDC;          // Saves CDC passed in constructor
	CRect    m_rect;         // Rectangle of drawing area.
	BOOL     m_bMemDC;       // TRUE if CDC really is a Memory DC.
    
	void Construct(CDC* pDC)
	{
        ASSERT(pDC != NULL); 
		
        // Some initialization
        m_pDC = pDC;
        m_oldBitmap = NULL;
        m_bMemDC = !pDC->IsPrinting();
		
        if (m_bMemDC) {
            // Create a Memory DC
            CreateCompatibleDC(pDC);
            pDC->LPtoDP(&m_rect);
			
            m_bitmap.CreateCompatibleBitmap(pDC, m_rect.Width(), m_rect.Height());
            m_oldBitmap = SelectObject(&m_bitmap);
            
            SetMapMode(pDC->GetMapMode());
            pDC->DPtoLP(&m_rect);
            SetWindowOrg(m_rect.left, m_rect.top);
        } else {
            // Make a copy of the relevent parts of the current DC for printing
            m_bPrinting = pDC->m_bPrinting;
            m_hDC       = pDC->m_hDC;
            m_hAttribDC = pDC->m_hAttribDC;
        }
		
        // Fill background 
        FillSolidRect(m_rect, pDC->GetBkColor());
    }
	
	// TRK begin
public:
	CMemDC(CDC* pDC                  ) : CDC() { pDC->GetClipBox(&m_rect); Construct(pDC); }
	CMemDC(CDC* pDC, const RECT& rect) : CDC() { m_rect = rect           ; Construct(pDC); }
	// TRK end
    
	virtual ~CMemDC()
	{        
        if (m_bMemDC) {
            // Copy the offscreen bitmap onto the screen.
            m_pDC->BitBlt(m_rect.left, m_rect.top, m_rect.Width(), m_rect.Height(),
                this, m_rect.left, m_rect.top, SRCCOPY);            
            
            //Swap back the original bitmap.
            SelectObject(m_oldBitmap);        
        } else {
            // All we need to do is replace the DC with an illegal value,
            // this keeps us from accidently deleting the handles associated with
            // the CDC that was passed to the constructor.            
            m_hDC = m_hAttribDC = NULL;
        }    
    }
    
    // Allow usage as a pointer    
    CMemDC* operator->() 
    {
        return this;
    }    
	
    // Allow usage as a pointer    
    operator CMemDC*() 
    {
        return this;
    }
};

#endif
